Polyisocyanurate

ABSTRACT

AN IMPROVED POLYISOCYANURATE COMPRISING POLYMETHYLENE POLYPHENYLISOCYANATE HAVING A FUNCITIONALITY OF 2.1 TO 3.2 AND HAVING AN EQUIVALENT WEIGHT BETWEEN 120 AND 180; A POLYOL HAVING AN EQUIVALENT WEIGHT BETWEEN 30 AND 100; A TERTIARY AMINE; AN N-SUBSTITUTED AZIRIDINE; AN ORGANIC EPOXIDE, AND A BLOWING AGENT. THESE COMPOSITIONS EXHIBIT AND ADVANTAGEOUS CREAM TIME AND FIRM TIME AND A REDUCED FRIABILITY.

United States Patent "O 3,799,896 POLYISOCYANURATE Ernest K. Moss, St.Petersburg, Fla., assignor to The Celotex Corporation, Tampa, Fla.

No Drawing. Continuation-impart of abandoned application Ser. No. 4,050,Jan. 19, 1970. This application May 8, 1972, Ser. No. 251,279

int. Cl. (108g 22/44 U.S. Cl. 260--2.5 AW 23 Claims ABSTRACT OF THEDISCLOSURE CROSS-REFERENCE TO RELATED APPLICATIONS This application is acontinuation-in-part of US. application Ser. No. 4,050, filed Jan. 19,1970, now abandoned.

DISCLOSURE Compositions of matter which cure to produce polyisocyanuratefoams are well known in the art. However, for many industrialapplications, it is necessary that these compositions have a cream timeof 15 to 30 seconds and a firm time of 25 to 60 and preferably 25 to 50seconds. This is to permit utilization of the composition incommercially available apparatus. Furthermore, the desired cream timeand firm time must be achieved without adversely affecting the physicalproperties of the resultant foam. The physical property most oftenaffected is friability. However, other physical properties such asdensity, flammability, closed cell percent, compressive strength,flexural strength, and thermal stability can also be adversely affected.

Accordingly, it is the object of the present invention to provide animproved composition of matter which is substantially free of one ormore of the above disadvantages of prior compositions.

Another object is to provide an improved composition of matter whichexhibits a cream time of 15 to 30 seconds, a firm time of 25 to 60seconds and a friability less than 35 percent.

A further object of the present invention is to provide an improvedcomposition which has the above-described cream time, firm time, andfriability Without adversely affecting the other physical properties ofthe resultant foam.

According to the present invention, there is provided an improvedcomposition of matter comprising: polymethylene polyphenylisocyanatehaving a functionality of 2.1 to 3.2 and having an equivalent weightbetween 120 and 180; a polyol preferably a diol having an equivalentweight between 30 and 100; a tertiary amine; an N-substituted aziridine;an organic epoxide; a blowing agent, and a surfactant.

3,799,895 Patented Mar. 26, 1974 "ice THE POLYMETHYLENE POLYPHENYLISOCYANATE In the broadest aspect of the present invention, anypolymethylene polyphenylisocyanate having the indicated functionalityand indicated equivalent weight can be employed. Those polymethylenepolyphenylisocyanates having a functionality of less than 2.1 aregenerally not acceptable because the resultant foams exhibit anundesirably high friability. Polymethyelne polyphenylisocyanates havinga functionality greater than 3.2 also produce foams of too great afriability. Therefore, the polymethylene polyphenylisocyanates of thepresent invention generally have a functionality of 2.1 to 3.2 andpreferably 2.3 to 3.0.

Polymethylene polyphenylisocyanates having an equivalent weight lessthan tend to produce foams having too great a friability. Those havingan equivalent weight greater than 180 are generally too viscous to maketheir use practical. Therefore, the polymethylene polyphenylisocyanatesemployed in the present invention generally have an equivalent weightbetween 120 and 180 and preferably have an equivalent weight between and145.

A preferred subclass of polymethylene polypheny1isocyanates especiallyuseful in the present invention are a mixture of those of Formula I:

wherein n is an integer from O to 8 and wherein the mixture has theabove-described functionality and equivalent weight. This mixture shouldhave a viscosity between 100 and 40,000 and preferably 250 to 2500centipoises measured at 25 C. in order to be practical for use in thepresent invention.

Examples of suitable polymethylene polyphenylisocyanates useful in thepresent invention include those of Formula I, wherein n is l as well asmixtures wherein n can have any value from 0 to 8 as long as the mixturehas the specified equivalent weight. One such mixture has 40 weightpercent of 21:0, 22 weight percent of 11:1, 12 weight percent of n=2 and26 weight percent of 11:3 to about 8. The synthesis of polymethylenepolyphenylisocyanates is described in Seeger et al. US. Pat. 2,683,730and in Powers US. 3,526,652 at column 3, lines 6-21. It should,therefore, be understood that the polymethylene polyphenylisocyanateavailable on the market under the trade names Papi and Mondur MR cansuccessfully be employed within the spirit and scope of the presentinvention.

Toluene diisocyanate and diisocyanatophenyl-methane both of which arecommonly employed in prior art compositions, are unsuitable for use inthe present invention. Both of these compounds have a functionality ofonly 2, which is below the indicated range. Furthermore, toluenediisocyanate has an equivalent weight of less than 120, which is belowthe desired range for equivalent weight. In the practice of the presentinvention it is not necessary to exclude all amounts of these twoisocyanates as long as the mixture of organic polyisocyanates has afunctionality and an equivalent weight within the specified range.

NCO

3 THE POLYOL In the broadest aspects of the present invention, anypolyol having an equivalent weight between 30 and 100, and preferablybetween 30 and 70 and having a functionality between 2 and 3, and havingat least two hydroxyl groups which pass the Zerewitinolf Test, can beemployed in the present invention. Diols are preferred, although triolsand higher polyols can be employed in minor amounts generally less than10% admixed with diols provided the equivalent weight of the mixture iswithin the specified range. The preferred diols are those of Formula II:

wherein R is selected from the group consisting of lower alkylene andlower alkoxyalkylene with at least two carbon atoms. Examples ofsuitable diols include, among others, ethylene glycol, propylene glycol;1,3 propanediol; 1,4-butanediol; diethylene glycol, dipropylene glycol,dimethylol dicyclopentadiene, 1,3-cyclohexanediol; and 1,4-cyclohexanediol.

In order to ensure complete reaction, the polymethylenepolyphenylisocyanate and the polyol are generally mixed in an equivalentratio of 2:1 to 6:1 and preferably 3:1 to 4:1. In ranges outside theseproportions the reaction yields a product having undesirable physicalcharacteristics. At higher ratios the product has an undesirably highfriability. At lower ratios the product has an undesirably highflammability.

THE TERTIARY AMINE A wide variety of tertiary amines can be employed inthe present invention as long as they are soluble in either thepolymethylene polyphenylisocyanate or the polyol. One preferred class oftertiary amines are compounds of Formula III:

(III) wherein R R and R are independently selected from the groupconsisting of alkyl, aryl, aralkyl, and alkaryl. Tertiary aminescontaining more than one amino nitrogen are also suitable. Examples ofsuitable tertiary amines include, among others, ortho(dimethylaminomethyl) phenol, tris (2,4,6-dimethyl aminomethyl) phenol,trimethylaminopropylpiperazine, 1,4 diazabicyclo[2.2.2] octane,tetramethylethylene diamine, tetramethylpropane diamine.

The preferred tertiary amine is tris(2,4,6-dimethyl aminomethyl) phenol.The tertiary amine generally comprises from 0.01 to 5, and preferablyfrom 0.1 to 2, weight percent of the composition.

THE N-SUBSTITUTED AZIRIDINE In the broadest aspect of the presentinvention, any N-substituted aziridine which is soluble in either thepolymethylene polyphenylisocyanate or the polyol can be employed in thepresent invention. However, the preferred N-substituted aziridines arecompounds of Formula IV:

(IV) CH2 rim wherein R is alkyl, aryl, aralkyl, alk'aryl, hydroxyalkylor alkoxyalkylene. Examples of suitable N-substituted aziridinesinclude, among others, N-methyl aziridine, N- ethylaziridine, N (2hydroxyethyl) aziridine, N-(dimethylaminopropyl) aziridine, benzylaziridine, chloropropyl aziridine, phenyl aziridine and N-(ethoxyethyl)aziridine. The preferred N-substituted aziridine is N-(2-hydroxyethyDaziridine. The N-substituted aziridine generally comprisesfrom 0.01 to 5, and preferably from 0.1 to 2, weight percent of thecomposition.

THE EPOXIDE In the broadest aspects of the present invention, anyepoxide can be employed which is soluble in either the polyol or thepolymethylene polyphenylisocyanate. One preferred class of epoxides arethose of Formula V:

wherein R is hydrogen, alkyl, aryl, aralkyl, alkaryl, orhydroxyalkylene. Another group of suitable epoxides includes thediepoxides. Examples of suitable epoxides include, among others,ethylene oxide, propylene oxide, butene oxide, the glycidyl ethers ofbisphenol A, resorcinol, phenol and other substituted phenols andaliphatic alcohols; styrene oxide, vinyl cyclohexane dioxide,dipentenedioxide, alloocimene dioxide, and bis (2,3-epoxycyclopentyl)ether. The epoxide generally comprises from 0.1 to 10, and preferablyfrom 0.5 to 5, weight percent of the composition. In lesser amount thefirm time of the compositions is undesirably great, whereas in greateramounts, the heat of the exothermic reaction tends to discolor the foam.

THE BLOWING AGENT Any blowing agent characteristically employed insimilar prior art products can be employed in the composition of thepresent invention. In general, these blowing agents are liquids having aboiling point between 0 C. and C. Examples of suitable blowing agentsinclude, among others, chlorinated and fluorinated hydrocarbons such asfluorotrichloromethane which is the preferred blowing agent. The blowingagents are employed in an amount sufiicient to give the resultant foamthe desired bulk density which is generally between 0.5 and 10, andpreferably between 1 and 5 pounds per cubic foot. The blowing agentgenerally comprises from 1 to 30, and preferably comprises from 5 to 20,parts by weight of the composition. When the blowing agent has a boilingpoint at or below ambient, it is maintained under pressure until mixedwith the other components. Alternatively, it can be maintained atsubambient temperatures until mixed with the other components.Difluorodichloromethane is the preferred blowing agent having a boilingpoint below 25 C. at atmospheric pressure.

THE SURFACT ANT Successful results have been obtained with silicone/ethylene-oxide/propylene-oxide copolymers as surfactants. The surfactantmolecules act as nucleating points from which bubbles can be initiallyformed and they further stabilize the bubbles after formation to allowpreparation of foam. Among the many surface-active materials mentionedinthe patent literature as cell-size control agents and stabilizers forurethane foams are alkoxy silanes, polysilylphosphonates, polydimethylsiloxane and polydimethylsiloxane-polyoxyalkylene block copolymers. Fora more detailed explanation of the function of the surfactant in themanufacture of foamed polyurethane and polymethylenepolyphenylisocyanate compounds, reference is made to an article entitledHow Silicone Surfactants Affect Polyurethane Foams in Modern Plastics,January 1967 edition, pp. 133 if, of which Robert J. Boudreau is theauthor.

Examples of surfactants useful in the present invention include, amongothers, polydimethylsiloxane-polyoxyalkylene block copolymers availablefrom the Dow Corning Corporation under the trade name DC-193.

The surfactant generally comprises from 0.05 to 4, and preferablycomprises from 0.1 to 2, weight percent of the composition.

THE rnocess The compositions of the present invention are simplyproduced by mixing the components with the result that foaming andcuring take place. The resultant can then be cut and shaped bywell-known methods. The mixing can be accomplished at widely varyingtemperatures, but is generally accomplished at 0 to 50 C., andpreferably at to 30 C. The ideal temperature is C. At lowertemperatures, the cream time is undesirably long, whereas at highertemperatures, the cream time and firm time are undesirably short.Furthermore, at higher temperatures there is a tendency for the foam tochar because of the added heat due to the exothermic reaction.

The components of the composition of the present invention canbe mixedin any order. The preferred order is to produce a first component bymixing the polymethylene polyphenylisocyanate with the blowing agent. Asecond component is simultaneously produced by mixing the polyol, thesurfactant, and the epoxide. A third component is formed by mixing thetertiary amine and the N-substituted aziridine. The first component andthe second component are preferably intimately mixed, whereupon thethird component is added. It is upon addition of the third componentthat timing starts to determine the cream time and the firm time. Forcommercial use a high speed mixing device known in the art can be used.In this device all components are simultaneously metered directly intothe device.

EXAMPLES The invention is further illustrated by the following examplesin which all parts and percentages are by weight unless otherwiseindicated. These non-limiting examples are illustrative of certainembodiments designed to teach those skilled in the art how to practicethe invention and to represent the best mode contemplated for carryingout the invention.

EXAMPLE 1 This example illustrates the synthesis and properties of apreferred composition of the present invention.

The following quantities of the following ingredients are combined asindicated:

All ingredients are at 15 C. Items A and F are mixed in a first vessel.'Items B, E, and G are mixed in a second vessel. Items C and D are mixedin a third vessel. The contents of the first and second vessel are thenthoroughly mixed, whereupon the contents of the third vessel are added.An exothermic reaction ensues, eventually producing a foam. During thereaction the cream time and firm time are noted and are recorded inTable I. The friability of the cured composition is measured and theresults recorded in Table I.

EXAMPLES 2, 3, AND 4 These comparative examples illustrate compositionsnot within the scope of the present invention, wherein either theepoxide, the N-substituted aziridine, or the tertiary amine is missing.

The procedure of Example 1 is repeated employing the same times,conditions, and reactants, except that item C is omitted in Example 4,item D is omitted in Example 3, and item B is omitted in Example 2. Theresults are recorded in Table I.

By reference to Table I, it can be seen that by omitting the tertiaryamine (item C), an undesirably large firm time occurs. By omitting theN-substituted aziridine (item D) the firm time is out of limits on thehigh side notwithstanding an increase in item C necessary to keep thecream time within limits. Likewise, when the epoxide (item B) is omittedin Example 2, the firm time is un desirably great.

EXAMPLE 5 This comparative example of a composition not within the scopeof the present invention illustrates the undesirable results obtainedwhen a polyol of equivalent weight outside the desired range isemployed.

The procedure of Example 1 is repeated employing the same conditions,times, and ingredients, with the single exception that the ethyleneglycol is replaced by an equal amount of polyol 6-2410. By reference toTable I, it can be seen that the firm time is undesirably large and thefriability is undesirably great.

EXAMPLE 6 This comparative example of a composition not within the scopeof the present invention illustrates the nudesirable results obtainedwhen a high functionality polyol of equivalent weight outside thedesired range is employed at the same ratio of equivalents of hydroxylto isocyanate as the low equivalent weight diol. The procedure ofExample 5 is repeated employing the same conditions, times, andingredients with the exception that the sorbitol polyol, G-24l0, andisocyanate are added at a ratio of 1 equivalent of hydroxyl to 3equivalents of isocyanate group as in Example 1. By reference to TableI, it can be seen that the firm time is undesirably large and thefriability and flammability have increased. Flammability is measured as'burn extent and oxygen index. The polyol (6-2410) has an equivalentweight of 114 and a functionality of 6.

EXAMPLE 7 This comparative example of a composition not within the scopeof the present invention illustrates the undesirable results obtainedwhen a high functionality polyol of equivalent weight within the desiredrange is employed.

The procedure of Example 1 is repeated employing the same conditions,times, and ingredients, with the single exception that the ethyleneglycol is replaced by an equal amount of polyol 6-2406. By reference toTable I, it can be seen that the firm time is undesirably large andfriability is undesirably great. The polyol (6-2406) has an equivalentweight of 87.5 and a functionality of 6.

EXAMPLE 8 This comparative example of a composition not within the scopeof the present invention illustrates the undesirable results when a highfunctionality polyol of equivalent weight within the desired range isemployed at the same ratio of equivalents of hydroxyl to isocyanate asExample 1, i.e. 1:3.

The procedure of Example 7 is repeated employing the same conditions,times, and ingredients with the exception that the polyol, 6-2406, andisocyanate are added at a ratio of 1 equivalent of hydroxyl to 3equivalents of isocyanate as in Example 1. By reference to Table I, itcan be seen that the firm time is undesirably large and the fria'bilityis undesirably great and flammability is increased.

EXAMPLE 9 This example illustrates yet another composition of thepresent invention employing yet a dififerent isocyanate.

The procedure of Example 1 s repeated employing the same times,conditions, and ingredients, except that item A is replaced with 572grams of the mixture of iso- 7 cyanates produced in accordance wthExample 1 of US. Pat. 2,683,730, with similar results.

from dark brown to cream colored. This color change is also accompaniedby a simultaneous increase in volume.

TABLE I Example Number Example 1 1 2 3 4 5 6 7 8 (percent) OHzNCOequivalents.-. 1:3 1:3 1:3 1:10 1:3 1:3 1:9 1:3 Components:

A. Mondur MR 560 560 560 560 466 560 492 80. 5 B. Ethylene glycol 42 4242 42 6. 1

(3- 42 134 (3-2406 42 108 C. Tn's(2,4,6-dimethylamino methyl)- nhennl 44 0 9 10 10 8 .58 D. N-(2-hydroxyl ethyl) aziridine 4 4 0 8 9 10 10 8 58E. Propylene oxide 10 0 10 10 10 10 10 10 1. 43 F. CFCls 70 80 70 70 7575 75 70 10. 1 G. Surfactant 6 6 6 6 6 6 6 6 86 Results:

Cream time (seconds 18 20 17 21 25 21 21 Firm time (seconds) 45 70 200Inc. 95 75 90 Friability, 10 min., weight loss. 25 34 1 72 56 65 Burnextent, inches 10. 6 10. 7 10.5 9. 1 13. 1 9. 1 12. 7 Oxygen index 24. 924. 7 25. 4 26. 4 22. 7 26. 0 23. 2 Percent closed cells 86 87 Density,lbs/ft 1. 9 2. 2 2. 0 2. 1 2. 0 2. 0 1. 9

NorE.-Inc.=incomplete"reaetion is incomplete and has a firm time inexcess of 300 seconds.

EXAMPLE 10 This example illustrates another composition of the presentinvention.

The following quantities of the following ingredients are combined asindicated in Exarnpe 1.

Cream and firm times, density, burn extent, closed cell content,friability after 10 minutes, and weight loss at 300 C. were 18 and 44seconds, 1.85 lbs./ft. 10.6 inches, 85%, 25%,16%.

EXAMPLE 1 1 This comparative example illustrates the adverse effect onfirm time of eliminating the epoxide.

Example 10 is repeated employing the same times, conditions, andingredients, except that item E is omitted with the result that the firmtime is 70 seconds. This is an undesirably great firm time.

In the instant specification, for the definitions of R through Rinclusive, it will be understood that the preferred alkyl radicals arelower alkyl radicals, example of which include among other methyl,ethyl, propyl, isobutyl, t-butyl, and isooctyl. The preferred arylradicals are phenyl and naphthyl. The preferred alkaryl radical isbenzyl. The preferred aralkyl radical is phenyl substituted with 1 to 5,and preferably 1 or 2 lower alkyl radicals.

In the above examples the tri (2,4,6-dimethylaminomethyl) phenol is thatsupplied by the Rohm & Haas Chemical Company under the trade nameDMP-30.

In Examples 5, 6, and 7 the polyols employed are those sold by the AtlasChemical Company under the trade names Atpol G-2406 and Atpol G-2410having an equivalent weight of 87.5 and 114 grams per hydroxyl grouprespectively. These polyols are the propylene oxide adducts of sorbitolhaving hydroxyl number of about 640 and 490 respectively.

In the above examples, the N-(2-hydroxy ethyl) aziridine is thatsupplied by the Dow Chemical Company under the trade name SA-4051."

GLOSSARY Cream time.The time interval beginning with the addition of theN-substituted aziridine and the tertiary amine and ending when thecomposition changes color Unless otherwise indicated, the reactants aremixed at 15 C. under ambient conditions of atmospheric pressure and roomtemperature (25 C.).

Equivalent weight.-The molecular weight of the component divided by itsfunctionality. For example, ethylene glycol has a molecular weight of62.07 and has two hydroxyl groups or a functionality of 2. Therefore,the equivalent weight of ethylene glycol is 62.07/2 or approximately 31.The equivalent weight of the polymethylene polyphenylisocyanate is ofcourse determined by dividing the average molecular weight by theaverage number of isocyanate groups present per molecule. Theseequivalent weights can also be determined empirically.

Firm time.-The time interval beginning with the addition of theN-substituted aziridine and the tertiary amine and ending when thecomposition is sufiiciently cured such that a test specimen five inchesby one inch by one inch is self-supporting without sagging whensupported from its ends one inch off a table.

Burn extent.This is measured in terms of burn extent in the MonsantoTunnel, as described by M. M. Levy, Journal of Cellular Plastics, April1967, and by H. L. Vandersall, Journal of Paint Technology, 39, 494(1967). Conventional non-flame-retardant urethanes burn in excess of 23inches (length of tunnel), while moderately flame-retardant conventionalfoams burn 15-20 inches and highly flame-retardant conventional foamsburn 10-15 inches in this tunnel.

Friability.The propensity of the foam to break expressed in percentweight loss. This is determined by the ASTM C-421 friability testconducted for 10 minutes.

Thermal stability.The ability of the foam to maintain its weight atelevated temperatures. A temperature of 300 C. is used for all tests.Thermal stability is expressed as percent weight loss and is measured bythermogravimetric analysis according to the technique described by J. E.Sheridan et al. in the Journal of Cellular Plastics, May-June 1971.

Oxygen index.This is the measure of the flammability. The higher thenumber, the less flammable is the product. This is measured according toASTM D- 2863-70 except that a sample measuring /2" x A" x 6" is used. Areading of 24 or greater is desired.

What is claimed is:

1. A polyisocyanurate foam comprising the reaction product of:

(A) polymethylene polyphenylisocyanate (1) having a functionalit of 2.1to 3.2, and (2) having an equivalent weight between and 180, (B) apolyol having an equivalent weight between 30 and 100, and afunctionality between 2 and 3,

(C) a tertiary amine,

(D) an N-substituted aziridine,

(E) an organic epoxide,

(F) a blowing agent,

(G) a surfactant.

2. A composition of matter of claim 1, wherein the polyol is a diol.

3. A composition of claim 1 wherein the polymethylenepolyphenylisocyanate is a mixture of polymethylene polyphenylisocyanatesof Formula I:

I NCO CH:

wherein n is an integer from to 8, wherein the mixture has:

(a) a functionality of 2.1 to 3.2,

(b) an equivalent Weight between 120 and 180, and

(c) a viscosity of 250 to 2500 centipoises measured at 4. A compositionof matter of claim 1 wherein the polyol is one of Formula II:

(II) HOR --OH wherein R is lower alkylene or lower-al'koxy alkylene.

5. A composition of matter of claim 1 wherein the polyol consistsessentially of ethylene glycol.

6. A composition of matter of claim 1 wherein the tertiary amine is acompound of Formula III:

(III) R2 wherein R R and R are independently selected from the groupconsistin of alkyl, aryl, aralkyl and alkaryl.

7. A composition of matter of claim 1 wherein the tertiary amine is tris(2,4,6-dimethylaminomethyl) phenol. 8. A composition of matter of claim1 wherein the N-substituted aziridine is a compound of Formula IV:

(IV) CH wherein R is selected from the group consisting of alkyl, aryl,aralkyl, alkaryl, hydroxyalkyl and alkoxyalkylene.

9. A composition of matter of claim 8 wherein R is loweralkyl orhydroxyloweralkylene.

10. A composition of matter of claim 1 wherein the N- substitutedaziridine is N-(Z-hydroxyethyl) aziridine.

11. A composition of matter of claim 1 wherein the organic epoxide isone of Formula V:

wherein R is selected from the group consisting of alkyl, aryl, aralkyl,alkaryl, alkoxyalkylene, and hydrogen.

12. A composition of matter of claim 1 wherein the epoxide is vinylcyclohexane dioxide.

13. A composition of matter of claim 1 wherein the organic epoxide isethylene oxide.

14. A composition of matter of claim 1 wherein the organic epoxide ispropylene oxide.

15. A composition of matter of claim 1 wherein the blowing agent is aliquid having a boiling point between 0 C. and 100 C.

16. A composition of matter of claim 1 wherein the blowing agent isfluorotrichloromethane.

17. A composition of matter of claim 2 wherein:

the equivalent ratio of (A):(B) is 2:1 to 621, (C) comprises 0.01 to 5weight percent of the composition,

NCO NCO wherein the mixture has:

(a) a functionality of 2.1 to 3.2, (b) an equivalent weight between and180, (c) a viscosity between 250 and 2500 centipoises,

and (d) n is from 0 to 8, (B) a polyol having an equivalent weightbetween 30 and 60, and having Formula II:

wherein R is selected from the group consisting of loweralkylene andloweralkoxyalkylene, (C) a tertiary amine of Formula III:

wherein R R and R are independently selected from the group consistingof alkyl, aryl, aralkyl, and alkaryl,

(D) an N-substituted aziridine of Formula IV:

wherein R is selected from the group consisting of alkyl, aryl, aralkyl,alkaryl, hydroxyalkyl, and alkoxyalkylene,

(E) an organic epoxide of Formula V:

CH,-CH-Ro wherein R is selected from the group consisting of alkyl,aryl, aralkyl, alkaryl, alkoxyalkylene, and hydrogen, (F) a blowingagent, (G) a surfactant,

wherein,

the equivalent ratio of (A):(B) is 2:1 to 6:1,

(C) comprises 0.1 to 2 weight percent of the composition,

(D) comprises 0.1 to 2 weight percent of the composition,

(E) comprises 0.5 to 5 weight percent of the composition,

(F) comprises 5 to 20 weight percent of the composition,

(G) comprises 0.1 to 2 weight percent of the composition.

NCO

s teen wherein:

30 to 50 weight percent are compounds of Formula I wherein n is 0,

15 to 30 weight percent are compounds of Formula I wherein n is 1,

5 to 15 weight percent are compounds of Formula I wherein n is 2,

the balance are compounds of Formula I wherein n is 3 to 8,

(B) ethylene glycol,

(C) tris(2,4,6-dimethylaminomethyl) phenol,

(D) N-(Z-hydroxyethyl) aziridine,

(E) propylene oxide,

(F) fiuorotrichloromethane,

(G) a surfactant, wherein:

the equivalent ratio of (A):(B) is 2:1 to 6:1,

(C) comprises to 2 weight percent of the composition,

(D) comprises 0.1 to 2 weight percent of the composition,

(E) comprises 0.5 to 5 weight percent of the composition,

(F) comprises 5 to 20 weight percent of the composition,

(G) comprises 0.1 to 2 weight percent of the composition, wherein thecomposition exhibits a cream time of 15 to 25 seconds and a firm time of30 to 60 seconds and wherein the cured composition has the physical formof a foam having a friability less than 35 percent.

20. A process for producing a polyisocyanurate foam comprising:

(I) admixing:

(A) polymethylene polyphenylisocyanate (1) having a functionality of 2.1to 3.2,

and

(2) having an equivalent weight between 120 and 180,

(B) a polyol having an equivalent weight between 30 and 100, and havinga functionality between 2 and 3,

(C) a tertiary amine,

(D) an N-substituted aziridine,

(E) an organic epoxide,

(F) a blowing agent, and

(G) surfactant,

(II) recovering the polyisocyanurate foam.

21. The process of claim 20 wherein the admixing is conducted underambient pressure at an initial temperature of 0 to 50 C.

22. A process of claim 20 for producing a polyisocyanurate foamcomprising:

(I) admixing at 0 to 50 C.:

(A) polymethylene polyphenylisocyanate which is a mixture ofpolymethylene polyphenylisocyanates of Formula I:

NCO NCO wherein the mixture has:

(a) a functionality of 2.1 to 3.2,

(b) an equivalent weight between and (c) a viscosity between 250 and2500 centipoises, and

(d) n is from 0 to 8.

(B) a polyol having an equivalent weight between 30 and 60, and havingFormula II:

HO--R -OH wherein R is selected from the group consisting loweralkyleneand loweralkoxyalkylene, (C) a tertiary amine of Formula III:

(III) wherein R R and R are independently selected from the groupconsisting of alkyl, aryl, aralkyl, and alkaryl, (D) an N-substitutedaziridine of Formula IV:

(IV) CH9 NR' C 1 wherein R is selected from the group consisting ofalkyl, aryl, aralkyl, alkaryl, hydroxyalkyl, and alkoxyalkylene, (E) anorganic expoxide of Formula V:

CH2CH-R wherein R is selected from the group consisting of alkyl, aryl,aralkyl, alkaryl, alkoxyalkylene, and hydrogen, (F) ,a blowing agent,

(G) a surfactant, wherein,

the equivalent ratio of (A):(B) is 2:1 to 6:1, (C) comprises 0.1 to 2weight percent of the composition, (D) comprises 0.1 to 2 weight percentof the composition, (E) comprises 0.5 to 5 weight percent of thecomposition, (F) comprises 5 to 20 weight percent of the composition,(G) comprises 0.1 to 2 weight percent of the composition, and then (II)recovering the polyisocyanurate foam. 23. A polyisocyanurate foamcomprising the reaction product of:

(A) polymethylene polyphenylisocyanate (1) having a functionality of 2.1to 3.2, and (2) having an equivalent weight between 120 and (B) ethyleneglycol, (C) tris(2,4,6-dimethylaminomethyl) phenol, (D)N-(Z-hydroxyethyl)aziridine, (E) propylene oxide, (F)fluorotrichloromethane, and (G) a surfactant.

FOREIGN PATENTS 5/1971 Canada 260-25 AW MAURICE J. WELSH, 1a., PrimaryExaminer US. Cl. X.R.

252188.3, 426; 260-2.5 AC, 77.5 NC

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 3,799,896 Dated March 26 1974 Inventofl Ernest K. Moss It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 4, line 58, "inthe" should read as -in the-- Column 6 line 73 "5"should read as -is- Table I, OH:NCO equivalents, example 4, "1:10"should read as Table I, OH:NCO equivalents, example 5, 1:3" should readas Column l0, line 45 Formula IV should read as I In all appropriateformulae the nitrogen atom of the NCO group is attached to the benzenering.

Signed and sealed this 30th day of July 1974.

(SEAL) Attest:

MCCOY M. GIBSON, JR. 0. MlXRStIALL DANN Attesting Officer Commissionerof Patents FORM PO-105O (10-69) USCOMM-DC e037s-p69 a us. sovznnmzmPRINTING OFFICE: 1969 0-366-334 UNITED STATES PATENT OFFICE CERTIFICATEOF CORRECTION Patent No. 3,799,896 Dated March 26 1974 lnventofl ErnestK. Moss It is certified that error appears in the aboveidentified patentand that said Letters Patent are hereby corrected as shown below:

Column 4, line 58, "inthe" should read as --in the-- Column 6 line 73,"s" should read as -is- Table I, OHzNCO equivalents, example 4, "1:10"should read as Table I, OH=NCO equivalents, example 5, 1:3" should readas Column l0, line 45 Formula IV should read as In all appropriateformulae the nitrogen atom of the NCO group is attached to the benzenering.

Signed and sealed this 30th day of July 1974.

(SEAL) Attest:

MCCOY M. GIBSON, JR. Attesting Officer C. MARSHALL DANN Commissioner ofPatents FORM PO-105O (10-59) USCOMM-DC 60376'P69 a uis. GOVERNMENTPRINTING ornc: 19" 0-3004 A

